Exercise stair devices having continous-loop moving-stair components are known. Ehrenfield in U.S. Pat. No. 4,848,737 discloses a moving ladder exercise device whose speed is regulated by a microprocessor to keep the climbers heart-rate constant. Chang in U.S. Pat. No. 4,726,581 discloses a stair-climbing simulation device having a speed-reduction brake system that makes use of a controlled hydraulic resistance to regulate the speed. Sarno et al., U.S. Pat. No. 4,822,029 discloses an exercise simulator having channel members, pivotally mounted to offer various degrees of steepness. None of these devices simulate a rock climbing situation and, specifically, none of them provide a flat climbing surface or a safe, inexpensive structure suitable for rock climbing practice.